Double revolving disc refiner

ABSTRACT

An improved double-revolving disc refiner wherein an annular shield member is attached to the input member of the refiner so as to project into the feed-end disc, thereby blocking off leakage paths around seals positioned at the joint of the input member and feed-end disc. Means are included for injecting a water phase into the clearance space between the shield member and the disc&#39;&#39;s seal, so as to force the water phase to flow downstream with respect to the stock flow through the joint, out of the clearance space and away from the joint.

United States Patent 1191 1111 3,746,270

Moore, Sr. July 17, 1973 [54] DOUBLE-REVOLVING DISC REFINER 1.758.5395/1930 Schuchardt 241/251 [75] Inventor: Robert D. Moore, Sr., Danv1lle,Va. Primary Emminer Granvie Y. Custer Jr.

1 3] A gn e United States yp m C mpany, Attorney-George E. Verhage, DanaM. Schmidt Chicago, 111. et a1.

[22] Filed: June 25, 1971 [57] ABSTRACT An improved double-revolvingdisc refiner wherein an annular shield member is attached to the inputmember 52 11.5. c1. 241/251 of the refiner Se as Prejeet into thefeed-end dise, 51 1111.01. B02c 7/06 thereby blocking off leakage p hsaround seals 051- [58] Field of Search 241 /244, 250, 251, honed at theJoint of the input member and feed-end 241/255 256 disc. Means areincluded for injecting a water phase into the clearance space betweenthe shield member [56] References Cited and the disc's seal, so as toforce the water phase to flow downstream with respect to the stock flowthrough UNITED STATES PATENTS the joint, out of the clearance space andaway from the 3,219,282 11/1965 Horstman 1. 241/255 x joint 1,039,3269/1912 Schroeder 241/251 6 Claims, 7 Drawing Figures 52 56 kI/Z I m 2I00 2 1 40 I6 I4 54 34 38 Patented July 17, 1973 2 Sheets-Sheet l Fig. I

Robert D. Moore, Sr.

INVENTOR Dana M. Schmidt George E. Verhage John Kenneth Wise ATTORNEYSPatented July 17, 1973 3,746,270

2 Sheets-Sheet B 54 Robert D. Mo0re,Sr.

Fig. 7 INVENTOR Dana M. Schmidt BY George E. Verhage John Kenneth WlseATTORNEYS DOUBLE-REVOLVING DISC REFINER BACKGROUND OF THE INVENTION Theprocess of making hardboard, a dense, durable substitute for naturalwood, includes the steps of chipping lumber, refining the chips intoindividual cellulosic fibers, forming a wet mat from the fibers, andsimultaneously heating and compressing the mat to form the hardboard.The refining step utilizes, as the step indicates, a refiner usually ofthe type which forces chips and chip fragments obtained from a digesterto pass between two counter-rotating discs, which separate or refine thefragments into individual fibers. This step is crucial, as any chipfragments which bypass the refiner and find their way into the board matwithout first being refined cause unacceptable blemishes in high qualityhardboard. Such blemishes not only destroy the otherwise randomappearance of the fibers in the board, they cause swelling on thesurface which prevents the board from taking a flat, highly glossedsurface such as is necessary for high quality board.

For the last several years, attempts to use a refiner having a highcapacity or rate of input of stock have failed to produce high qualityboard due to the fact that chip fragments have bypassed the rotatingdiscs. Such bypassing of chips was in the nature of leakage whichoccurred at the joint between the feed-end disc and the input housing,the former rotating at a high rate of speed with respect to the latter.It is customary to incorporate seal rings at the aforesaid joint, butprior to the invention even seal rings did not prevent chip fragmentsfrom being forced into the joint until the seal rings had worn so muchthat the fragments completely bypassed the refiner and fell into thedischarge chute.

Such wear on the seal rings placed a premium on careful and accuratealignment of the rings when assembled, such as after each maintenancedisassembly, as well as on a design which permitted adjustment of therings to take up the slack due to the wear. In spite of these expensiveand time-consuming steps, the chip fragments continued to leak and wearthe rings. It was found necessary, therefore, to attempt to correct thesituation by replacing the seal rings as they wore out beyond theiradjustment capabilities. However, not only have replacement rings beendifficult to obtain from the manufacturer of the refiner, their use hasbeen prohibitively expensive both in cost and inactive down time. Forexample, the seal rings on the Bauer No. 412 Refiner made by the BauerBrothers Co. cost about $1,000 to replace, and in the making ofhardboard such replacement has been found to be necessary on thatrefiner as much as ten times a year. Each seal replacement ties up theuse of the refiner and requires accurate realignment.

Because of all these difficulties, both the manufacturers and the usersof high capacity refiners have been attempting to find a solution to theleakage problem ever since such refiners were first used to make highquality hardboard. Such attempts have included the redesign of the sealrings themselves, but until the development of this invention, theseattempts have generally failed.

SUMMARY OF THE INVENTION The disclosure concerns an improved fiberrefiner having rotatable free-end and control-end discs, the jointbetween the feed-end disc and input housing or member of which has beendesigned so as to prevent essentially all fragment leakage and so as togreatly reduce seal ring wear, thereby maintaining quality. Morespecifically, there is provided in a refiner in which the rotating discadjacent to the input member is sealed with respect to the member by aring positioned in a male sealing relationship with respect to themember, an annular shield member attached to the input member so as tobe in a male relationship with respect to the ring. Such shield membercovers the potential leakage path. Also, there is provided means forinjecting a water phase into the path formed between the malefittingshield member and the ring so as to flow opposite to chip fragmentsattempting to leak out via this path, so as to further enhance thewearability of the construction.

Accordingly, it is an object of the invention to provide an improvedrefiner wherein stock leakage is substantially eliminated without theneed for continually replacing seal rings.

It is a related object of the invention to provide a refiner which iscapable of continuously and inexpensively producing uniformly highquality hardboard.

It is a further object of the invention to provide in such a refinermeans for countering the tendency of stock to follow a leakage path outof the refiner.

Other objects and advantages will become apparent upon reference to thefollowing drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially sectioned,fragmentary elevational view of an improved cellulosic refinerconstructed in accordance with the invention;

FIG. 2 is a perspective view, partially in section, of portions of theinput member, illustrating both a portion of the improvement as well asthe mounting relationship of the input member with respect to the feedend drive shaft;

FIG. 3 is an end elevational view of the input member illustrated inFIG. 2;

FIG. 4 is an enlarged, fragmentary, sectional view similar to FIG. 1 butillustrating only the top portion of the joint of the feed-end disc'andthe input member;

FIG. 5 is an enlarged, fragmentary sectional view similar to FIG. 4, butillustrating the bottom portion of the joint;

FIG. 6 is an end elevational view of one portion only of the inputmember, illustrating another embodiment of the invention; and

FIG. 7 is a side elevational view of the input member portionillustrated in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the invention isdescribed hereinafter in connection with a particular high capacityrefiner, it is not limited thereto and can be applied to any refiner inwhich leakage of the stock at the feed end disc is a problem. Forexample, high pressure refiners which force stock betweendouble-revolving discs by means of steam are considered to be asdefective in stock leakage as those not operating under steam pressure.Furthermore, the invention, hereinafter described in con nection withthe refining of wood chips to make hardboard, is not limited to that usealone. Rather, any use of the refiner having the construction of theinvention is contemplated as being included.

Any reference herein to top," bottom, or other directional adjectives ismeant to refer to that portion of the described structure as it ispositioned when assembled in the refiner.

Turning now to FIGS. 1 and 2, there is illustrated a high capacitycellulosic fiber refiner, such as the Bauer No. 4 l 2 Refiner referredto above, which has been improved by means of the instant invention.Such refiner conventionally includes a feed end 10, a control end 30,and a refining stage 50. The feed end comprises a feed-end motor l2, afeed-end drive shaft 14 driven by the motor 12, hearing housings 16 and18 supporting the shaft 14, and a motor enclosure 20. The control end 30comprises parts which are mirror images, essentially, of the feed end10, namely a motor 32, drive shaft 34, and bearing housings 36 and 38.In addition, however, bearing housing 38 is provided with a thrustplate, not shown, which cooperates with a hydraulic cylinder 40 so as toadjust the clearance between the rotating discs in the refining stage50. That stage 50 has an input member 52, otherwise known as the stockinlet. The input member is split into two portions 54 and 56, the topportion 56 of which has twin inlet spouts 58 and 60. (See FIG. 2.) Thesespouts define a passageway 61 which opens into a feed end disc 64contained within a disc enclosure 62. Also enclosed therein is thecounter-rotating control end disc 66, each of the discs being mounted onits respective drive shaft. This construction permits disc 64 to rotatewith respect to the input member 52. The disc 64 is peculiar in that ithas threepassageways 68 leading from passageway. 61 to the outer edge ofthe disc. Only one passageway 68 is shown.

Turning now to FIG. 4 and 5 in particular, the disc 64 is provided witha stock inlet sealing ring 80 attached thereto by bolts, not shown,which ring is conventionally mounted so as to be positioned in a malesealing relationship with respect to the input member 52. For example, aspecial input member seal 82 can be attached to input member 52,dimensioned so as to accommodate seal ring 80 therewithin. To permitrelative adjustment of the seal ring 80 and the seal 82 due to wearheretofore experienced, the mating surfaces 84 and 86 of the sealringand the seal, respectively, have been beveled as shown particularly inFIG. 5. Except for the construction provided by the invention,hereinafter described, the seal ring 80 fits against portion 56 and 54of the input member 52 (FIG. 4 and 5), in such a way as to define aspace or path 89 which extends generally perpendicularly from thepassageway 61 at .the junction of the disc and the input member. Path 89thus becomes a potential leakage of chips out of the refiner and intothe discharge chute, in spite of the fact that portions 54 and S6 of theinput member 52 are provided with shoulders 90 and 92, respectively,which project inwardly beyond the limits of the passageway within disc64 (FIG. 4).

The assembly and operation of the refiner described above isconventional, and is adequately described, for example, in the operationmanual entitled Double Revolving Disc Refiner No. 412 published by BauerBrothers Co. of Springfield, Ohio. Briefly a fiber source such asdigested wood chips, which are now softened fragments, are fed into thetwin spouts 58 and 60 from a defibering stage. If the motors l2 and 32are about L000 horsepower each, the rate of input can be the highcapacity type of about 50 to 100 tons a day. The

chips and chip fragments are forced through passageways 61 and 68 arounddrive shaft 14, in the direction of the arrow labeled 94 (FIGS. 4 and5). The centrifugal force of the rotation drives them into the gapbetween the two discs 64 and 66, where they are milled into individualfibers, which fibers drop out a discharge chute 96 (FIG. I). From therethey are conventionally washed and cleaned, or sent through apump-through refiner, after which they are formed into a wet mat.

TI-IE IMPROVEMENT Turning now to FIGS. 2 through 5 in particular, inaccordance with one aspect of the invention, an annular shield member100 is attached to the input member 52 so as to occupy a malerelationship with respect to the sealing ring 80. Specifically, themember 100 is attached to the shoulders and 92 of the portions 54 and56, thus covering the path 89. Like the input member 52 itself, theshield member is split to permit mounting of the member 52 around thedrive shaft. In the embodiment shown in FIGS. l-S, the shield member iswelded as at 102 (FIG. 4). Because of the relative rotation of ring 80with respect to shield member 100, a clearance or spacing 104 isprovided between them, this spacing extending and being directed onlydownstream, with respect to the direction of stock flow as indicated byarrow 94, proceeding from the shoulders 90 and 92 of the input member.This construction changes the potential chip leakage path from one whichis about a 90 angle turn from normal stock flow, to one which amounts toa complete reversal of flow. It will be appreciated that this reversalis resisted by the overall flow by the stock as indicated by arrow 94.The construction can also be described as one in which the position ofthe sealing ring has been altered so as to be confined within a groovedefined by seal 82 of input member 52 and by shield member 100.

To further prevent stock flow from passing other than through theconfines of the shield member 100, the two portions of the shoulder 92which conventionally are cut away and represent the outermost limit ofthe passageway 61 in portion 56, are filled in by metal pieces 106 cutto size and welded to the housing (FIGS. 2 and 3).

In accordance with yet another aspect of the invention, it has beenfound that the introduction of a water phase into the spacing 104 toflow downstream as indicated by arrows 110 further counters any reversalflow of chips and thereby cooperates with shield member 100 to preventleakage of chips. Specifically, referring to FIGS. 4 and S, the topportion 56 is drilled or otherwise machined so as to include apassageway 1 12 which opens out into the beginning of spacing 104.,Twoof these may be provided, for example, in the top portion. Similarly twoholes 114 are preferably machined into shoulder 54 (see also FIG. 6) andlarger holes 115 are drilled coaxially therewith and threaded (FIG. 5).The holes 1 14 can even pass partially through the outer portions of theshield member 100. A nipple is screwed into each of the two holes 115. Ahose I22 (FIG. l)'is attached to each nipple I20, and a similar nippleand hose (not shown) can be connected to the passageways 112 in topportion 56. Water or steam is then delivered to the passageways 112 andnipples 120, and thence out into spacing 104, thus flowing in adirection parallel to and cocurrent with the flow of fibers conveyedinto the refiner by said input member. In the case of water, the linepressure delivered to the nipples must exceed 80 psi.

Other sources of water will be readily apparent. For example, a ring ofmany nipples 120 or passageways 1 12 could be provided instead of twoeach as described above, if a more uniform delivery of the water phaseis desired. Also, the use of two nipples 120 only, on bottom portion 54of the input member, can provide adequate counter-washing.

FIGS. 6 and 7 illustrate an alternate embodiment of the invention,specifically one in which the shield member is bolted on instead ofbeing welded. Parts similar to those previously described are identifiedby the same numerals, to which the distinguishing suffix a has beenadded. Thus, bottom portion 54a has attached to shoulder 90a, a shieldmember 100a which projects above the face of the shoulder the samedistance as in the previous embodiment. Holes 114a are drilled throughthe housing as in the previous embodiment. However, unlike the previousembodiment, shield member 100a is removably attached to the input memberby means such as machine screws 130 (FIG. 6). To further secure theshield member, the face of the shoulders, such as shoulder 90a, ismachined to provide a groove 132 dimensioned to accommodate the trailingedge of the shield member (FIG. 7), recessed within the shoulder.

It will be readily appreciated that the embodiment of FIGS. 6 and 7 hasthe advantage of removability.

The shoulder member in either embodiment can be made from a variety ofmaterials and in a variety of sizes. One representative example which isin no way limiting is a construction wherein member 100 or 100a projectsoutwardly from the shoulder a distance of three-fourths of an inch, hasan annular thickness of seven-sixteenths of an inch, and in the case ofthe removable embodiment, is recessed into a groove onefourth of an inchdeep. Such a shield member was constructed from 304 stainless steel, but316 stainless is just as suitable.

The use of the above-described specific shield construction incombination with water injection obtained by two nipples 120 in a BauerNo. 4l2 Refiner was found to provide a marked improvement in the qualityof hardboard made with this refiner, and'a drastic reduction of wear onthe part of the seal ring 80 and the seal 82.

Although the invention has been described in connection with certainpreferred embodiments, it is not limited thereto. Rather, it is intendedthat it cover all equivalents, embodiments, and alternate arrangements,as may be included within the scope of the following claims.

What is claimed is:

1. In a cellulosic fiber refiner comprising at least one rotatable disc,means for rotating the disc, an input member for conveying a source ofthe fibers to said disc, the member having at least one passagewayopening into said disc, and a sealing ring attached to the discpositioned in a male sealing relationship with respect to said member;the improvement comprising an annular shield member attached to saidinput member so as to be in a male relationship to said ring, saidshield member covering the potential leakage path created by thejunction of the sealing ring and the input member adjacent to saidpassageway.

2. The improved refiner as defined in claim 1, wherein said ring ispositioned with respect to said passageway so as to define a potentialleakage path extending generally perpendicularly from said passageway,and said shield member is spaced from said ring so as to permit relativerotation between said shield member and said ring, said spacingextending only downstream from said leakage path with respect to theflow of the source of fibers to said disc, whereby fiber sources mustexecute generally a complete reversal of flow to leak out through saidleakage path 3. The improved refiner as defined in claim 2, and furtherincluding means for injecting a water phase into said spacing in adirection parallel to and cocurrent with the flow of fibers conveyedinto the refiner by said input member, whereby the water phase countersany fiber source which might otherwise make said reversal of flow.

4. In a cellulosic fiber refiner comprising at least one rotatable disc,means for rotating the disc, an input member for conveying a source ofthe fibers to said disc, the member having at least one stock passagewayopening into said disc, and a sealing ring attached to the disc; theimprovement comprising an annular shield member attached to said inputmember so as to be in a male relationship to said ring, the spacebetween said ring and said shield member being directed downstream only,with respect to the flow of the source of fibers through saidpassageway, and means for injecting a water phase into said spacedownstream with respect to said fiber source flow, whereby the waterphase counters any fiber source which might otherwise flow into saidspace.

5. The improved refiner as defined in claim 4, wherein said ring isconfined within a groove formed by said shield member and said inputmember.

6. The improved refiner as defined in claim 4 and further including agroove in the face of said input member adjacent to said disc andwherein said shield member is removably attached to said input memberwithin said groove.

1. In a cellulosic fiber refiner comprising at least one rotatable disc,means for rotating the disc, an input member for conveying a source ofthe fibers to said disc, the member having at least one passagewayopening into said disc, and a sealing ring attached to the discpositioned in a male sealing relationship with respect to said member;the improvement comprising an annular shield member attached to saidinput member so as to be in a male relationship to said ring, saidshield member covering the potential leakage path created by thejunction of the sealing ring and the input member adjacent to saidpassageway.
 2. The improved refiner as defined in claim 1, wherein saidring is positioned with respect to said passageway so as to define apotential leakage path extending generally perpendicularly from saidpassageway, and said shield member is spaced from said ring so as topermit relative rotation between said shield member and said ring, saidspacing extending only downstream from said leakage path with respect tothe flow of the source of fibers to said disc, whereby fiber sourcesmust execute generally a complete reversal of flow to leak out throughsaid leakage path.
 3. The improved refiner as defined in claim 2, andfurther including means for injecting a water phase into said spacing ina direction parallel to and cocurrent with the flow of fibers conveyedinto the refiner by said input member, whereby the water phase countersany fiber source which might otherwise make said reversal of flow.
 4. Ina cellulosic fiber refiner comprising at least one rotatable disc, meansfor rotating the disc, an input member for conveying a source of thefibers to said disc, the member having at least one stock passagewayopening into said disc, and a sealing ring attached to the disc; theimprovement comprising an annular shield member attached to said inputmember so as to be in a male relationship to said ring, the spacebetween said ring and said shield member being directed downstream only,with respect to the flow of the source of fibers through saidpassageway, and means for injecting a water phase into said spacedownstream with respect to said fiber source flow, whereby the waterphase counters any fiber source which might otherwise flow into saidspace.
 5. The improved refiner as defined in claim 4, wherein said ringis confined within a groove formed by said shield member and said inputmember.
 6. The improved refiner as defined in claim 4 and furtherincluding a groove in the face of said input member adjacent to saiddisc and wherein said shield member is removably attached to said inputmember within said groove.